Arc stacks suppress the electrical arc created between a stationary contact and the movable contact of a circuit breaker blade as the blade moves from a closed position to an open position during a fault condition. One type of arc stack, designated in FIG. 1 as reference numeral 100, includes a plurality of identical, generally rectangular plates positioned and interconnected parallel to one another. The plates have respective identically-shaped arc throats to form a passageway for the moveable blade. To maximize performance of the arc stack, the passageway formed by interconnecting the plates with the respective individual arc throats follows the radius of the moveable blade as it opens. This is accomplished by laterally offsetting the identical arc plates relative to one another in the same direction so that the individual arc throats follow the radius of the moveable blade. Thus, the arc stack takes on an elongated curved shape.
A drawback of this type of arc stack is that it is difficult to manufacture with automated equipment because its construction requires complex manipulation of the circuit breaker components surrounding the arc stack.
Another drawback of this type of arc stack is that it takes up a significant amount of space within the circuit breaker enclosure. Referring to the arc stack of FIG. 1, for example, due to the irregular shape of the arc stack, it occupies an unnecessarily large volume within the enclosure.
In addition to overcoming the foregoing drawbacks, it is desirable to construct an arc stack which dissipates the electrical arc in a more efficient manner, thereby resulting in reduced pressures, higher exit voltages, lower let-through currents, and improved circuit breaker interruption.
Moreover, there is an ongoing effort to reduce the cost and size of circuit breakers while reducing the labor required to assemble and maintain the circuit breakers.